This invention relates to an aluminum evaporator core for an automotive air conditioning system and, more particularly, to such core having a metallic copper coating to inhibit microbial growth.
A typical automotive air conditioning system comprises an evaporator core located at the front of the passenger compartment for cooling an air stream entering the compartment from outside the vehicle or circulated from the compartment. The evaporator is generally formed of an aluminum alloy not only because of the high thermal transfer properties that accelerate air cooling, but also because sheets of such alloy are readily formed by stamping and brazing to manufacture the evaporator. As the air cools, moisture tends to condense onto exterior surfaces of the evaporator. This moist environment promotes the growth of bacteria or fungi and, if such growth becomes excessive, may produce an unpleasant odor or other condition that adversely affects passenger comfort.
Cupric salts are known to be effective fungicides and bactericides. Common cupric salts are water soluble so that a mere application of such salt to an evaporator would wash away with the voluminous condensate that drains from the core and thus be effective for only a brief time. Rather, it is desired to inhibit microbial growth over an extended time suitable for automotive components.
It is an object of this invention to provide an evaporator core formed of an aluminum alloy to take advantage of its high heat transfer properties and ready formability, and having a coating which generates cupric ions effective to inhibit microbial growth and continues to generate such cupric ions over an extended period of time such as is required for automotive use.